"I know that the main problem in Vidal's $80 million (47 million pound) transfer from Juventus to Manchester United is Louis van Gaal's doubt over the improvement of Arturo's knee," Sampaoli told the Chilean publication El Mercurio.

Rumors have persisted all summer long that a deal for the Chilean midfielder was nearing completion, but with the Premier League season start looming on Aug. 16, there is still no official word on whether or not Vidal will make the move from Turin to Manchester. Currently, signs point to no.

Sampaoli went on to say in the interview that he believed Vidal was only at 30 to 40 percent of his fitness at the World Cup. Vidal underwent knee cartilage surgery in May and his World Cup manager hinted that perhaps the player had pushed too hard to get back in time to play in Brazil.